Flame-retardant finish for cellulosic textile materials

ABSTRACT

A flame-retardant finish for cellulosic textile materials, the method of applying it and the textile materials treated with the flame retardant. More particularly, the flame-retardant finish comprises an aqueous solution of tris(hydroxymethyl)phosphine (THP) or tris(alkoxymethyl)phosphine (formula I), a methylolated nitrogenous cellulose reactant and, optionally, urea. P(CH2OR)

United States Patent Richard Frederick Stockel Bridgewater Township, Somerset County; Samuel James O'Brien, Dunellen; Robert George Weyker, North Plalnfield, all of NJ.

[72] Inventors [54] FLAME-RETARDANT FINISH FOR CELLULOSIC TEXTILE MATERIALS 9 Claims, No Drawings [52] U.S.Cl 8/116.3, 8/116 P, 117/136,117/137,2S2/8.1 [51] Int. Cl ..D06m13/14, D06m 13/28,C09k 3/28 [50] Field ofSearch 252/8.l', 117/136,137,143,144,145;161/191;8/116P, 116.2, 116.3

[ 56] References Cited UNITED STATES PATENTS 2,809,941 10/1957 Reeves et al 161/191 X 2,810,701 10/1957 Reeves etal ll7/136X 2,937,207 5/1960 Rcuter et a1. 117/136 X 3,257,460 6/1966 Gordon et a1... 52/81 3,45 2,098 6/1969 Vullo 25 2/8.] OTHER REFERENCES Reeves et a1. Flame Retardants for Cotton Using APO-and APSTHPC Resins," Textile Research Journal, Vol 27, No. 3, Mar., 1957, pp. 260- 266. Flame Retardant Gets Plant-Scale Trial Chemical and Engineering News, Sept. 9, 1968, pp. 42 and 43.

Primary E.raniiner.lohn T. Goolkasian Assistant Examiner-D. .1. Fritsch A!!0rneyCharles J. Fickey ABSTRACT: A flame-retardant finish for cellulosic textile materials, the method of applying it and the textile materials treated with the flame retardant. More: particularly, the flame retardant finish comprises an aqueous solution of tris(hydroxymethyhphosphine (THP) or tris(alkoxymethyl)phosphine (formula 1), a methylolated nitrogenous cellulose reactant and, optionally, urea,

P(CH OR) FLAME-RETARDANT FINISH FOR CELLULOSIC TEXTILE MATERIALS This invention relates to a flame-retardant finish for cellulosic textile materials, to the method of applying it and to the textile materials treated with the flame retardant. More particularly, the flame-retardant finish comprises an aqueous solution of tris(hydroxymethyl)phosphine (THP) or tris(alkoxymethyl)phosphine (formula I), a methylolated nitrogenous cellulose reactant and, optionally urea.

P cn,oR),

In formula I, R is hydrogen or lower alkyl.

Certain derivatives of THE, such as tetrakis(hydroxymethyl)phosphonium chloride (THPC) of formula II and tris(hydroxymethyl)phosphine oxide (TI-IPO) of formula III, are components of flame-retardant systems. U.S. Pat. No. 2,809,941 and other references disclose the use of polymeric condensation products of THPC and/or TI-IPO with methylolated nitrogenous compounds as flame retardants for cellulosic textile materials. Cellulosic textile materials treated with flame-retardant amounts of TI-IPC and/or TI-IPO and the coreactant nitrogenous compound have certain deficiencies, including tensile strength loss and undesirable hand characteristics such as stiffening.

cu (cn,on

oncmom,

III

It is therefore an object of this invention to provide a flameretardant composition for cellulosic textile materials using a phosphine compound.

A further object is to provide such a finish whereby a good hand is retained by the treated textile material.

These and other objects of the invention will become apparent as the description thereof proceeds.

It has not been discovered that textile finishes containing tris(hydroxymethyl)phosphine or tris(alkoxymethyl)phosphine and a methylolated nitrogenous cellulose reactant impart durable flame-retardant properties to cellulosic textile materials without significant sacrifice of tensile strength or softness of hand. The cellulosic textile materials thus treated exhibit a high degree of flame retardancy which is durable to repeated laundering.

Tris(hydroxymethyl)phosphine (TB?) is an old compound, its manufacture having been disclosed at least as early as 1960 (U.S.S.R. Pat. No. 138,617). (Its preparation is also the subject of American Cyanamid, US. Pat. No. 3,243,450, with utility disclosed as a gasoline additive.) Tris(alkoxymethyl)phosphine can be prepared by reacting TI-IP with a lower alcohol in the presence of a strong acid such as hydrochloric acid.

Examples of useful methylolated nitrogenous cellulose reactants include aminoplast resin precursors such as methylol melamine, methylol ureas, methylol carbamates, etc., and their alkylated derivatives. The methylol compounds contain two or more methylol groups per molecule of nitrogenous compound. The preferred reactants are methylol melamines and their alkylated derivatives.

Representative melamine compounds include dimethylol melamine, dimethylated trimethylol melamine, hexakis(methoxymethyl) melamine, partially methylolated pentamethylol melamine, etc. Representative urea compounds include dimethylol urea, tetramethylol urea, methylated dimethylol urea, dimethylol ethylene urea, etc. Representative carbamate compounds include dimethylol methyl carbamate, dimethylol ethyl carbamate, dimethylol hydroxyethyl carbamate, etc. Combinations of the above methylolated nitrogenous compounds may also be used.

The components of the fire retardant finish can be applied to the textile material from the same bath or from separate baths by padding, dipping, spraying, etc. For maximum durability it is of advantage to dry the textile at a temperature of about 75 to 1 15 C., preferably at to 1 10 C., before the finish is cured at a temperature from about to l75 C., preferably at l40 to l60 C. The time required for curing is between 1 and 5 minutes, depending on the temperature used and the weight of the fabric.

In another procedure, tris(hydroxymethyl)phosphine or tris(alkoxymethyl)phosphine, nitrogenous compound and formaldehyde are applied to the textile material.

In a third procedure, tris(hydlroxymethyl)phosphine, nitrogenous compound and fonnaldehyde are reacted, either partially or completely, in aqueous medium before application to the textile material. Water soluble products are obtained.

The amount of tris(hydroxymethyl)phosphine or tris(alkoxymethyl)phosphine applied to the cellulosic textile material should be between 15 and 50 weight percent, preferably between 20 and 25, based on the weight of the textile material.

The amount of methylolated nitrogenous cellulose reactant, or alkylated derivative, applied to the cellulosic textile material will depend on the nitrogen content of the reactant. Sufficient reactant should be applied to provide, on a weight basis, between 50 and 300 percent of nitrogen, preferably between 100 and 200 percent, based on the phosphorus applied to the textile material. This relative amount of each compound may be determined by a calculation of the weight of nitrogen in the particular nitrogenous compound, calculating the amount of phosphorous according to the weight ratio stated and then the amount of phosphine which will contain that amount of phosphorous.

The addition of urea to the application bath improves the stability of the bath. It also improves the durability of the flame retardancy and reduces strength losses of the treated fabric. The amount of urea added to the bath should be at least 3 percent, preferably between 3 and 6 percent, based on the weight of the textile material.

The cellulosic textile material should contain at least 50 percent cellulosic fibers. By cellulosic fibers is meant such fibers as cotton, regenerated cellulose (rayon), linen, jute, etc. Blends of cellulosic fibers or blends of cellulosic fibers with noncellulosic fibers, both natural and synthetic, such as silk, wool, nylon, polyester, acrylic, etc., may be used.

EXAMPLE I PREPARATION OF TRIS( HYDROXYMETI-IYL)PHOSPHIN E An autoclave charged with 48 g. of paraformaldehyde and 104 g. of 44 percent aqueous formaldehyde was heated at 100 C., and phosphine was introduced in sufficient amount (about 34 g.) to maintain a pressure of 400 p.s.i. The product is a 68 percent aqueous solution of tris(hydroxymethyl)phosphine.

EXAMPLE II REACTION PRODUCT OF TRIS(HYDROXYMETHYL)Pl-IOSPHINE, MELAMINE AND FORMALDEHYDE A mixture of 25 g. of tris(hydroxymethyl)phosphine, 10 g. of malamine, 7.5 g. of formaldehyde and 17.5 g. of water was stirred at 65 C. for 1 hour. A clear solution was obtained.

EXAMPLE Ill METHYLATED REACTION PRODUCT OF TRIS(HYDROXYMETHYL)PHOSPHINE, MELAMINE AND FORMALDEHYDE A mixture of 50 g. of tris(hydroxyme'thyl)phosphine, 50 g. of melamine, 166 g. of 37 percent aqueous formaldehyde and I00 g. of water was stirred at 50 C. and pH of 7.5 (pH adjusted with sodium hydroxide) for about 3 hours. Methanol (150 ml.) and sufficient 30 percent hydrochloric acid to provide a pH of 6.06.5 were added. The resulting solution was concentrated by evaporation of 50 percent solids content.

EXAMPLE lV REACTION PRODUCT OF TRIS(HYDROXYMETHYL)PHOSPH1NE, MELAMINE AND FORMALDEHYDE A mixture of 33 g. of 60 percent tris(hydroxymethyl)phosphine, g. of malamine, 10 g. of 44 percent aqueous formaldehyde and 5 g. ofwater was heated at 55 C. and pH 8.0 for 2 hours. The product was a clear solution containing 55 percent solids.

Partially methylated trimethylol melamine having approximately two methylol groups.

The pad baths were applied to 80x80 cotton percale by a standard padding procedure obtaining a 100 percent wet pickup. The padded fabrics were dried at 107 C. for 2 min.

and then heated at 159 C. for 5 min. The fabrics were I thoroughly washed with water and dried at 107 C.

The durability of the flame-retardant finishes to laundering was determined by repeatedly washing the fabrics in an automatic washing machine, using water at 140 C. and a commercial detergent and drying in a tumble dryer. After each washing operation, the flame resistance of the fabrics was determined by a vertical flame test according to Standard Test Method AATCC 34-1966. The washings and flame testing were continued as long as the char length of the burnt fabric was less than 6 inches. The limit of wash durability was reached when the char length was 6 inches. The results are shown in table 1. Fabrics A, B and C correspond to pad baths A, B and C.

TABLE 1 Nov washes before failure 17 7 When the methylol melamine was omitted, the flame test failed after one wash.

EXAMPLE VI An aqueous pad bath containing 50 percent of the product of example 11 and 5 percent of urea was applied to 80 80 cotton percale by a standard padding procedure obtaining a 100 percent wet pickup. The treated fabric was dried at 107 C. and then heated at 150 C. for 3 min. The fabric was washed in warm water and dried.

The durability of the flame retardant finish to laundering was determined by the procedure of example V to be at least 50 washes.

EXAMPLE Vll An aqueous pad bath containing 20 percent of the product of example III, 10 percent of urea, and 6 percent of an aminoplast resin comprising 75 percent of methylated hexamethylol melamine and 25 percent methylol urea was applied to x80 cotton percale by a standard padding procedure obtaining a percent wet pickup. The treated fabric was dried at 107 C. for 2 min. and then heated at 159 C. for 4 minutes.

The durability of the flame-retardant finish to laundering was determined by the procedure of example V to be about 8 washes.

EXAMPLE Vlll An aqueous pad bath containing 50 percent of the product of example IV and 5 percent of urea was applied to 80 80 cotton percale by a standard padding procedure obtaining a 100 percent wet pickup. The treated fabric was dried at 107 C. for 8 minutes and then heated at 149 C. for 3 minutes.

The durability of the flame-retardant finish to laundering was determined by the procedure of example V to be at least 40 washes.

EXAMPLE IX A mixture of 62 g. of tris(hydroxymethyl)phosphine, 93 g. of a 60/40 mixture of l,3-dimethylol-5-hydroxyethyltetrahydrotriazone and polymethylolurea (about 3.2 methylol groups per mole of urea), and 122 g. of water was heated at pH 9.5 and 60C. for 5 hours. A clear solution was obtained.

EXAMPLE X An aqueous pad bath containing 56 percent of the product of example IX, 8.5 percent of partially methylated trimethylol melamine and 6.4 percent of 85 percent phosphoric acid was applied to 80 80 cotton percale by a standard padding procedure obtaining an 80 percent wet pickup. The treated fabric was dried at 107 C. for 4 minutes and then heated at 150 C. for 4 minutes.

The durability of the flame-retardant finish to laundering was determined by the procedure of example V to be at least 45 washes.

For pH adjustment.

We claim: 1. A flame-retardant finish for cellulosic textile materials comprising phosphine of the formula wherein R is hydrogen or lower alkyl, and methylolated nitrogenous cellulose reactant.

2. A finish as in claim 1 where the methylolated nitrogenous cellulose reactant is a methylolated melamine.

3. A process for imparting a flame-retardant finish, as in claim 1, to cellulosic textile materials comprising applying tris(hydroxymethyl)phosphine or tris(alkoxymethyl)phosphine of the formula P(CH OR) 

2. A finish as in claim 1 where the methylolated nitrogenous cellulose reactant is a methylolated melamine.
 3. A process for imparting a flame-retardant finish, as in claim 1, to cellulosic textile materials comprising applying tris(hydroxymethyl)phosphine or tris(alkoxymethyl)phosphine of the formula P(CH2OR)3 where R is hydrogen or lower alkyl, and methylolated nitrogenous cellulose reactant.
 4. A cellulosic textile material treated by the process of claim
 3. 5. A finish as in claim 1 comprising in addition, formaldehyde.
 6. A finish as in claim 5 wherein said ingredients are at least partially reacted together.
 7. The finish of claim 1 where the phosphine is tris(hydroxymethyl)phosphine.
 8. The finish of claim 1 where the nitrogenous reactant is melamine.
 9. The finish of claim 1 containing in addition, urea. 